Engineering manual - UniSAB III 1.10.8
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001930 en 2021.06
Compressor control and surveillance
Fig. 21: Capacity vs speed diagram, SMC 116 E with CFA 140/200 coupling.
For CMO types and a standard setting where minimum speed is set to 700 [rpm], motor rpm min. 2 is
set to 900 [rpm] and maximum speed is 1800 [rpm], the reciprocating compressor will be step/speed
regulated up to 50% and then speed regulated between 50% and 100%.
Capacity vs speed diagram , S MC 11 6 E VS D wi thC F A140/200 coupling
Minimum speed: 700 rpm
Speed (rpm)
Capacity %
005100010050
0
1 0
2 0
3 0
4 0
5 0
6 0
7 0
8 0
9 0
10 0
Black line: SPEED mode (optimised for best regulation)
Red line: S T EP mode (optimised for best COP)
4 cyl
8 cyl
Blue line: both SPEEDand STEP mode
Dashed line s : transient operation only
Note: Actual allowed speed range depends on operating conditions and motor selection.
Dotted red line shows regulation by utilising total
unloading and/or compressor start/stop
16 cyl
12 cyl